Money in my savings account earns interest at 10% annual rate. Each time I go to the bank, I waste 15 minutes in line. My time is worth $10 per hour. During each year, I need to withdraw $10,000 to pay my bills.
a How often should I go to the bank?
b Each time I go to the bank, how much money should I withdraw?
c If my need for cash increases, will I go to the bank more often or less often?
d If interest rates rise, will I go to the bank more often or less often?
e If the bank adds more tellers, will I go to the bank more often or less often?